This invention relates to control systems, particularly to missile control systems, and more particularly to missile control systems utilizing fiber optics in the seeker head thereof.
In missiles, especially in rolling type missiles which utilize a free gyro stabilized heat sensing mechanism for controlling wing surfaces of either the variable area or variable incidence type, one of the greatest problems is in providing an efficient control system therefor. As illustrated in FIG. 2 of U. S. Pat. No. 3,010,677, an infrared seeker head is used to provide a measurement of angular rate of the missile-to-target line of sight. The entire optical unit is a part of a rotating gyro mass or rotor. As illustrated in the above cited patent, the optical portion of the head is a Cassegrain telescope wherein incident energy is reflected by the gyro-mounted primary mirror onto a secondary mirror and focused onto a spinning reticle or chopper. Light passing through the reticle falls on an infrared cell which converts heat energy pulses to electrical pulses, the cell being stationary with respect to the telescope.
The reticle serves two functions in an infrared seeker: It provides discrimination against certain unwanted targets such as cloud edges and it permits sensing of tracking error by chopping the radiation passing to the sensitive cell.
One problem of the prior known control systems utilizing a free gyro stabilized heat sensing mechanism having a rotating reticle system is that the reticle chopping efficiency approaches zero as the target image approaches boresight. Because of this effect, automatic gain control (AGC) information cannot be derived whereby seeker loop gain can be effectively controlled.
This invention provides a means of overcoming the above problem by placing a fiber optical element in association with the reticle for translation of an image to a more favorable reticle radius to effect efficient chopping.
Therefore, it is an object of this invention to provide a control system.
A further object of the invention is to provide a control system for rolling missiles.
Another object of the invention is to provide a control system for rolling missiles or the like utilizing a free gyro-stabilized heat sensing mechanism incorporating a spinning reticle or chopper.
Another object of the invention is to provide a control system for rolling missiles or the like utilizing a free gyro-stabilized heat sensing mechanism incorporating fiber optics in cooperation with spinning and fixed reticles.
Another object of the invention is to provide a light energy chopping mechanism with fiber optics for translation of an image to a more favorable chopper radius to effect efficient chopping.